The primary objective of this study is to compare the effect of an investigational, non-adherent dressing to a commercial wound dressing, 3M™ Tegaderm™ Matrix Dressing with PHI™ technology (Matrix dressing), in the management of diabetic foot ulcers. Subjects' wounds will be observed for a four week, pre-treatment period with wound assessments being made and samples of wound fluid and tissue collected and analyzed to characterize the wound. Following this pre-treatment observational stage, subjects continuing to meet inclusion/exclusion criteria will be randomly assigned, with stratification by center, wound size and wound duration, in either of two groups in the eight week treatment stage of the study. Subjects in one group will have their wound managed with an investigational non-adherent dressing, and subjects in the other group will have their wound managed with a Matrix dressing. At Visit 4 (start of the treatment stage of the study), subjects with a study wound that is less than 1 cm2 at this point will be dropped from the study. A second investigational device will be used to measure the pH of the wound, which will be compared to wound healing data.